The invention relates generally to polymers and, more particularly, to a method for reacting halogenated vinyl polymers with epoxides and to polymer products resulting from such reaction.
Halogenated vinyl polymers exhibit thermoplastic properties and are used in a wide variety of applications including as membranes, packaging films, coatings, electrical cable insulation coatings, sheets, pipes, composites, sealants, and adhesives impact modifiers. Such polymers are also used as sensor material in pressure and temperature monitoring applications.
Many of the above applications require enhancement of the durability of the halogenated vinyl polymers. The durability of such polymers may be chemically increased by using curing agents such as amines and peroxides with an acid acceptor, e.g. benzoyl peroxide, magnesium oxide. Radiation processes have also been utilized to cure polymers of the type described.
Surface modifications of halogenated vinyl polymers have also been effected to achieve the desired surface properties such as hydrophilicity for enhanced membrane process flux or improved wettability for better adhesive binding. For example, Schonhorn et al., in Journal Adhesion Science Technology, Vol. 3, No. 4, pages 277-290 (1989), disclose the grafting of epoxides onto polyvinylidene fluoride (PVDF) through the use of amine and amide coupling agents to produce a strong adhesive bond bridging the epoxy resin and PVDF. The amine/amide curing agent reacts with PVDF to modify the surface region and then cross-links the epoxy resin to the fluoropolymer through a diamine functionality than was previously bonded to backbonds of the fluoropolymer.
Epoxy resins are known to be reactive with aliphatic and aromatic acids and polyorganic acids, organic acid anhydrides and polyanhydrides, sulfones, polysulfones and the like. Lee et al., Handbook of Epoxy Resins, McGraw-Hill (1967).
Epoxy resins have been blended with PVDF, such as disclosed in U.S. Pat. No. 3,784,506, to achieve better corrosion resistance. The resulting mixture, however, is a blend of the epoxy resin and PVDF and no reaction occurs between the epoxy resin and PVDF.
Ramesh and De in Journal of Materials Science, Vol. 26, pages 2846-2850 (1991) have reported that melt-mixed blends of poly(vinyl chloride) and epoxidized natural rubber become cross-linked at elevated temperatures in the absence of any cross-linking agent. The products are described as having good oil resistance, high abrasion resistance, low resilience, and high modulus with moderate tensile and tear strength. Temperatures in excess of 140.degree. C. are required to cause cross-linking of the poly(vinyl chloride) and epoxidized natural rubber.